Process for cleaning copper containing metal articles



Patented Sept. 19, 1950 PROCESS FOR CLEANING come ooN A TAINING METAL ARTICLES 7 ep J. Bayer, Blackwood; N. J.

. No Drawing. Application September 17 1947, I Q

Serial No. 7 74;G90. l 1. a,

(Granted under the act of March f3, 183,. as

amended April 30, 1928; 3700.'G.w757) The present invention concerns a process for cleaning a copper containing metal article and in particular concerns a process which includes both heat and chemical treatment of the copper-containing article.

In welding with an acetylene torch the burner tip of the torch becomes corroded with use and it is necessary either that the burner tip be discarded or reconditioned by cleaning. The corrosive material formed on the burner tip largely comprises carbon and also oxides and other compounds of the metal from which the burner tip is fabricated. Thus burner tips, which are formed of a copper-containing material, such as brass, become corroded in the use by the formation of carbon and of oxides of copper, such as cuprous oxide and cupric oxide.

Because of the chemical and physical characteristics of the corrosive material and because of the high temperatures under which such corrosive material forms on the burner tip, there is a strong bond between the corrosive material and the metal of the burner tip. For this reason it is difficult and often impossible to remove such corrosive material by a simple wiping operation.

Formerl it has been customary to clean such corrosive material from the metal burner tip by an initial hand operation using emery cloth and by a final machining operation on a lathe to produce a polished surface, Also it has been customary to dress the ends of the tips by filing. This method of cleaning the corrosive material from the metal burner tips has the disadvantage of being inordinately time consuming. A further disadvantage resides in the fact that there is a tendency to chip and nick the burner tip with the result that the tips are rendered defective and dangerous to use.

The present invention overcomes these disadvantages by providing a cleaning process that does not involve the use of abrasive material and does not necessitate a machining operation. This process embodies the steps of initially heating the burner tip to a relatively high temperature followed by quenching the burner tip for a few seconds in a solution of zinc chloride followed by a final quenching in a water bath until the burner tip is cooled.

An object of the invention is to provide a process for cleaning a copper-containing metal article by heating the article and quenching the article in a zinc chloride solution.

Another object is to provide a process for cleaning a copper-containing metal article by heating the article and quenching the article in a solution of about one gallonlofwater solvent and about one pound of solute including about 93% by wei ht of zinc chloride and about 7% by weight of am-" mcnium' chloride." a i Further objectsand advantages. ofthis invention will be apparent from the following description and claims.

Heating of the burner tip can be accomplished with a tor-ch when the burner tip is supported upon refractory materials such as firebrick or the heating can be accomplished in an electric furname. The temperature to which the burner tip is heated can vary under different circumstances but in any event it is found desirable to heat the burner tip until the extremity thereof has a shimmering, irridescent appearance and this effeet is noted with a temperature of the order of 900 F.

The initial quenching solution includes water as a solvent and zinc chloride as a principal solute, and preferably also contains a minor proportion of ammonium chloride. A preferred composition includes about one gallon of water with about one pound of solute that comprises about 93% by weight of zinc chloride and about 7% by weight of ammonium chloride. Quenching of the heated burner tip in this bath can be for a period of time of the order of a few seconds.

Upon withdrawal of the burner tip from the zinc chloride quench the burner tip is immediately quenched in a bath of water until cool.

It is found that the process described is highly efiective in removing corrosion material from copper-containing metal burning tips and it is found that further reconditioning of the tips is unnecessary. Tips that are subject to the described process of treatment have a bright, clean surface. The mechanism by which the corrosion material is removed from the metal burner tips is not known in detail. It appears however, that the heating and quenching treatment in combination with the chemical treatment by a solution of zinc chloride and ammonium chloride produces a unique removal of the corrosion material,

It is to be understood that various. modifications and changes may be made in this invention without departing from the spirit and scope thereof as set forth in appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

l. A process for cleaning a copper-containing metal article comprising the steps of heating the article and quenching the article in a zinc chloride solution.

2. A process for cleaning a copper-containing metal article comprising the steps of heating the article to a temperature of about 900 and quenching the article in a zinc chloride solu tion.

3. A process for cleaning a copper-containing metal article comprising the steps of heating the article, quenching the article in a zinc chloride solution for a few seconds; followed immediately by quenching the article in a water bath until cool.

4. A process for cleaning a copper-containing metal article comprising the steps of heating the article and quenching the article in a solution comprising zinc chloride as aprincipal ingredient.

5. A process for cleaning a copper-containing metal article comprising the steps of heating the article and quenching the article in a soiution comprising zinc chloride and ammonium chloride.

6. A process for cleaning a copper-containing metal article comprising the steps of heating the article and quenching the article in a solution comprising about one gallon of water solvent and about one pound of solute including about 93% by weight of zinc chloride and about 7% by weight of ammonium chloride.

7, A process for cleaning a copper -contaimng metal article comprising the steps of heating the article to a temperature of about 900 F., quenching the article for a fewseconds in a solution comprising about one gallon of water'solvent and about one pound of solute including about 93% by weight of zinc chloride and about 7% by weight of ammonium chloride, followed immediately by vquenclriing the article in a water bath until cool.

JOSEPH J. BAYER.

BEFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,291,202 Bassett vJuly 28. 1942 

5. A PROCESS FOR CLEANING A COPPER-CONTAINING METAL ARTICLE COMPRISING THE STEPS OF HEATING THE ARTICLE AND QUENCHING THE ARTICLE IN A SOLUTION COMPRISING ZINC CHLORIDE AND AMMONIUM CHLORIDE. 